2004 Dodge Caravan Owner's Manual - Page 266

266 STARTING AND OPERATING FUEL REQUIREMENTS Your vehicle is designed to meet all emission regulations and provide excellent fuel economy when using high quality regular unleaded gasoline with an octane rating of 87. The use of premium gasoline is not recommended. The use of premium gasoline will provide no benefit over high quality regular gasolines, and in some circumstances, may result in poorer performance. Light spark knock at low engine speeds is not harmful to your engine. However, continued heavy spark knock at high speeds can cause damage and immediate service is required. Engine damage resulting from operating with a heavy spark knock may not be covered by the new vehicle warranty. Poor quality gasoline can cause problems such as hard starting, stalling and hesitations. If you experience these symptoms, try another brand of "regular" gasoline before considering service for the vehicle. Over 40 automobile manufacturers around the world have issued and endorsed consistent gasoline specifications (the World Wide Fuel Charter, WWFC) to define fuel properties necessary to deliver enhanced emissions, engine performance, and durability for your vehicle. The manufacturer recommends the use of gasolines that meet the WWFC specifications if they are available. Reformulated Gasoline Many areas of the country require the use of cleaner burning gasoline referred to as "Reformulated Gasoline". Reformulated gasolines contain oxygenates, and are specifically blended to reduce vehicle emissions and improve air quality.